Filter for liquids, in particular internal-combustion engine lubricant oils

ABSTRACT

A filter for liquids is disclosed herein. The filter includes a filter housing containing an exchangeable filter element. A support part is provided within the housing that is separable from the at least one filter element and extends at least partly centrally through the interior space of the filter element. A means is provided for releasably attaching one end of said support part to the filter housing. The housing includes first and second radial inner seals for separating a crude space surrounding an exterior of the filter element from a clean space located within interior of the filter element with the radial inner seals being mounted within the housing at the axial ends of the filter element. The filter element is folded star-shaped and sealed on the face side and provided on the inside at each of its two axial ends with a sleeve having an interior portion resting against the radial inner seals. The first radial seal includes an extension portion contained within a groove formed in the support part for separating the crude space from the clean space. An overflow valve is contained within the support part for establishing a flow connection between said crude space and said interior space when a pressure difference therebetween exceeds a predetermined value.

The invention relates to a filter for liquids, in particular alubricating-oil filter for an internal-combustion engine according tothe introductory part of claim 1.

Such a filter for liquids is known, for example from U.S. Pat. No.3,333,703. The filter for liquids shown there consists of a pot-shapedfilter housing which, at its one end, is connected with a mounting headvia a screw thread, and provided at its other open end with a screw-onhousing cover. A filter element supported in the interior of the filterhousing is provided with end disks and separates the crude space fromthe clean space. On the end disk of the filter element disposed oppositethe housing cover, an overflow valve is mounted which, under certainoperating conditions, establishes a connection between the crude spaceand the clean space. In connection with the other end disk of the filterelement and the closed end of the filter housing, provision is made fora return check valve. A drawback with said design is, on the one hand,the waste disposal of the filter element, which consists of all sorts ofdifferent materials, and, on the other hand, that when the filterelement is changed, at least the overflow valve is discarded because itis rigidly integrated in the end disk of the filter element.

A filter for liquids is known from U.S. Pat. No. 4,622,136 in connectionwith which a support part is supported in a separable filter housing,said support part receiving an annular filter element. Said annularfilter element, which itself has to effect a separation between thecrude and clean spaces by tightly resting against the support part, hasto be pushed with its total length over the support part, which meansdamaging of the filter element and/or a weakening of the sealing effectcannot be excluded.

A lubricating oil filter with a separable housing is known from DE-OS 3903 675, in connection with which a filter insert provided with face-sideend disks is rigidly connected with the housing cover, the latter beingscrewable to the filter housing. With said design, however, no provisionis made for a support part for receiving individual elements andextending at least partly centrally through the interior space of thefilter element, from which support part the filter element is separableand thus exchangeable alone.

Therefore, the problem of the present invention is to find a filter forliquids with a constructionally simple structure in connection withwhich the filter element can be discarded as waste separately and in away friendly to the environment, whereby the other functionallyimportant individual parts can be reused.

The solution to said problem is obtained with a filter for liquids withthe features according to the characterizing part of claim 1.

Advantageous developments of the invention are contained in thedependent claims.

Exemplified embodiments according to the invention are shown in thedrawing, in which:

FIG. 1 shows a sectional view of the filter for liquids according to theinvention;

FIG. 2 shows a sectional view of a second embodiment of a filter forliquids according to the invention;

FIG. 3 shows a partially sectional view of a third embodiment of afilter for liquids according to the invention;

FIG. 4 shows a sectional view of a fourth embodiment of a filter forliquids according to the invention; and

FIG. 5 shows a sectional view of a fifth embodiment of a filter forliquids according to the invention.

A filter for liquids 1 according to FIG. 1 consists of a pot-shapedfilter housing which, at its one end, is provided with the feed anddischarge openings 3 and 4, respectively, and connectable, for examplewith a mounting head, and at its other end closed by a removable housingcover 5. Provision is made for a seal 6 between the screw-on housingcover 5 and the filter housing 2. A filter element 7 made of paper isdesigned as a star filter and pocket-glued and separates the crude spacefrom the clean space 9. At each of its ends, it is provided on its innercircumference with a sleeve 10 made of strengthened paper. Furthermore,for stiffening the filter element 7, provision is made for a sleeve 11in the center zone of the filter element 7. The manufacture of such afilter element from a single material assures that when the filter ischanged, it can be discarded as waste in a way friendly to theenvironment.

In the filter housing, the filter element 7 is fixed by a sleeve-shapedsupport part 12 made of plastic, whereby the sleeves 10, which arerigidly joined with the filter element 7, rest against the seals 13, 14.The seal 13 is designed U-shaped and grips around the bottom end of thesupport part 12, so that a sealing is obtained at the same time betweenthe crude and clean spaces 8 and 9, respectively, and the interior 15 ofthe support part. The ring-shaped seal 14 is supported in the top zoneof the support part 12 in a matching groove 16. The support part 12consists of the two individual parts 12a, b, which are screwed to eachother via a thread. In an intermediate wall 17 of the lower individualpart 12b of the support part 12, provision is made for a return checkvalve 18, so that on the one hand, the purified lubricating oil can flowoff via the discharge opening 4 only starting with a predeterminedpressure, and, on the other hand, running dry of the filter is avoidedwhen the internal combustion engine is standing still. In anintermediate wall 19 of the top individual part 12 a of the support part12, provision is made for an overflow valve 20, which, at acorresponding pressure difference, established a connection between theinterior 15 of the support part 12 and the crude space 8. The topindividual part 12a of the support part 12 has the openings 21, whichestablish a connection between the clean space 9 and the interior 15 ofthe support part 12. In addition, the individual part 12a can be engagedwith the housing cover 5 via a snap connection 22, so that the housingcover 5 is screwed off from the filter housing 2, the filter element 7is removed together with the support part 12.

With such a filter for liquids, it is assured in a constructionallysimple way that when the filter element is changed, it can be disposedof as waste in a way friendly to the environment because of the singlematerial used, and that the individual parts such as the support part12, the valves 18, 20, and the seals 13, 14, which are required for thefunction, can be either reused or simply exchanged.

In the exemplified embodiment of a filter for liquids according to FIG.2, the same reference numerals are used as in FIG. 1 for identicalparts. These are:

    ______________________________________                                        Filter 1 for liquids                                                          ______________________________________                                        Filter housing 2                                                                           with screw-on housing cover 5                                    Feed opening 3                                                                Discharge opening 4                                                           Seal 6                                                                        Filter element 7                                                              Crude space 8                                                                 Clean space 9                                                                 Sleeve 10                                                                     Sleeve 11                                                                     Support part 12                                                                            with the individual parts 12 a, b, which                                      are connected with each other via a snap                                      connection 31                                                    Seal 14                                                                       Interior 15  of the support part 12                                           Groove 16    for the seal 14                                                  Intermediate wall 17                                                                       for receiving the return check valve 18                          Intermediate wall 19                                                                       for receiving the overflow valve 10                              Openings 21  for connecting the clean space 9 with the                                     interior 15 of the support part 12.                              ______________________________________                                    

The bottom individual part 12b of the support part 12, which alsoreceives a return check valve 18, is designed differently as compared tothe exemplified embodiment according to FIG. 1, and has a groove 24extending all around for receiving a seal 23. The lower end of theindividual part 12b changes into a disk 25 having the feed openings 3and, via a seal 26, rests against the filter housing 2. A return checkvalve 27 closing the feed openings 3 is supported in the individual part12b of the support part 12 as well.

The filter 1 for liquids is different from the exemplified embodimentaccording to FIG. 1 particularly in that a heat exchanger 28 (indicatedonly in rough outlines) is additionally integrated in the filter housing2, said heat exchanger being acted upon by the cooling water of theinternal combustion engine, whereby the feed and discharge of thecooling water takes place via a sleeve-shaped connection part 30, whichis fitted with the short feed and discharge pipe 29 and rotatablysupported (snap closure 31) on the housing part 2. For holding the heatexchanger 28, a sleeve-shaped connection element 32 made of metal isscrewed into filter housing 2, which connection element, at its top endrests sealed against the individual part 12b of the support part 12, andwhich, at its bottom end, has an inside thread 33 for connecting thefilter 1 for liquids with the internal combustion engine via knownmeans.

The properties and advantages stated with respect to the exemplifiedembodiment according to FIG. 1 apply to the exemplified embodimentaccording to FIG. 2 as well.

Another exemplified embodiment according to FIG. 3 contains a filter 40for liquids which is designed as a primary/secondary flow filter. Thefilter 40 for liquids, which is arranged upright, contains a pot-shapedfilter housing 41 made of aluminum pressure die-cast and a screw-onhousing cover 42 made of plastic, between which provision is made for aseal 43. At the closed end of the filter housing 41, provision is madefor feed and discharge ducts for the lubricating oil, whereby provisionis made for a discharge duct 44 leading to the points of lubrication forthe cleaned lubricating oil in the primary flow, and for a dischargeduct 45 leading into the crank space for the cleaned lubricating oil inthe secondary flow.

A primary-flow filter element 46 is made of paper (like the filterelement according to FIGS. 1 and 2) and designed in the form of a starfilter with glued pockets, and at each of its ends rigidly connected onthe inside by glueing with a sleeve 47 mde of strengthened paper.

A secondary-flow filter element 48 consists of stuffed cotton, which isreceived by an endless, ring-shaped hose 49 made of cotton. Since thetwo filter elements 46, 48 each consist of single materials, they can bedisposed of as waste in a simple way, also separately, in a mannerfriendly to the environment.

For holding the filter elements 46, 48 in the interior of the filterhousing 41, provision is made for a support part 50 made of plastic,which consists of the individual parts 51, 51a, 52, 53, which aremanufactured by the injection molding process and welded or glued toeach other. The individual part 51 consists of a central tube 54, towhich in its upper zone, an L-shaped sleeve 55 is shaped by molding inone piece in such a way that a clean space 58 for the cleanedlubricating oil of the secondary-flow filter element 48 is formedbetween the outer wall of the tube 54 and the longer leg 57 of theL-shaped sleeve 55, said longer leg having the openings 56. Said cleanspace 58 is connected with the interior 59 of the tube 54 via a throttlebore 60 disposed in the upper zone of the tube 54, so that the upperzone of the tube 54 acts at the same time as a standpipe. At its loweropen end, the tube 54 is sealingly supported in a short pipe 61receiving the discharge duct 45 for the cleaned lubricating oil of thesecondary-flow filter, whereby for receiving a return check valve 62,the lower end of the tube 54 is divided in two parts and the individualpart 51 a is connected with the individual part 51 via a snap connection63.

In order to obtain a ring-shaped pot part 64 for receiving thesecondary-flow filter element 48, the individual part 52 consists of aZ-shaped angle part 65 with legs of different length, of which anglepart the one leg 66 is provided with the openings 67 and forms the outerwall of the ring-shaped pot part 64, and of which the shorter leg 68rests against the tube 54, and of which the center bridge 69 restsagainst the short leg 70 of the L-shaped sleeve 55, whereby said partsare welded to each other. A sleeve-shaped extension 71 is shaped bymolding on the center bridge 69 as one piece, said extension beingsealingly supported in a short pipe 72 of the filter housing 2 andserving for receiving the primary-flow filter element 46, whereby theprimary-flow filter element 46 rests via its sleeves 47 rests againstthe seals 73, 74, which are supported in matching grooves.

In order to close the ring-shaped pot part 64 receiving thesecondary-flow filter and to prestress the secondary-flow filter element48, a cover 75 designed as a type of winged nut is screwed together withthe upper zone of the individual part 51 of the support part 50. Suchtermination and such prestress may be realized also, for example via acover part with a spring and bayonet lock.

A snap device 76 mounted on the top end of the individual part 51 of thesupport part 50 engages in a matching counterpart 77 mounted on thehousing cover 42, so that when the housing cover 42 is removed, thesupport part 50 together with the filter elements 46, 48 is removed atthe same time. With this, the individual part 51 a engaging the shortpipes 61, 72 and the sleeve-shaped extension 71 control the dischargeducts 44, 45 open, so that the oil present in the filter can drain off.

With other exemplified embodiments of a filter for liquids according toFIGS. 4 and 5, the same reference numerals as in FIGS. 1 and 2,respectively, are used for identical parts.

A star-shaped filter element 78 manufactured from paper is provided ateach of its ends on its inner circumference with a sleeve 79 made ofstrengthened paper, on which a paper end disk 80 is shaped by molding inone piece, sealingly closing the axial face edges of the filter element78. By manufacturing such a filter element from a single material, it isassured that said element can be disposed of as waste in anenvironment-friendly way when the filter is changed.

For receiving a part of the individual elements, a support part 81 isfixed on the housing cover 5 by means of the snap connection 82. A firstradial seal 83 separating the crude space 8 from the clean space 9 issupported on the support part 81, whereby, for example, an extension 84engages in a groove of the support part 81. In an intermediate wall 85of the support part 81, an overflow valve 20 is provided which, at acorresponding pressure difference, establishes a connection between thecrude space 8 and the clean space 9. In the interior of the support part81, additional provision can be made for a sieve 86. Furthermore, forsupporting the filter element 78, axially extending support ribs 87 areshaped by molding on the support part 81, distributed over the outercircumference of the support part.

For receiving a second radial seal 88 separating the crude space 8 fromthe clean space 9, a tubular short pipe 89 projecting into the interiorof the filter for liquids is molded as one piece onto the filter housing2 in the center. Via the sealing lips 90 molded onto said radial seal88, the latter can rest against the sleeve 79 arranged on the filterelement 78. Furthermore, a return check valve 91 blocking the feedopening 3 can be joined with the radial seal 88, forming one piece withthe latter. The return check valve 91 can be additionally elasticallyprestressed, for example via a spring metal sheet plate supported in theshort pipe 89. In order to prevent the clean space 9 from running dryduring an operational standstill, a return check valve 92 is fastened onthe short pipe 89, whereby its ring disk 93 is provided with the tongues94, the latter being distributed over the circumference and serving forsecuring the position of the radial seal 88.

The difference between FIG. 4 and FIG. 5 is that in FIG. 5, the snapconnection 82 is designed to be releasable. The filter of FIG. 5contains sieve 86.

The releasable snap connection between the housing cover 5 and thesupport part 81 comprises the four hook-shaped lugs 95, which arecircumferentially evenly distributed on the inner bottom of the coverand which project into the interior of the housing and engage inmatching, closed recesses 96 of the support part 81, said recesses beingprovided at that end of support part 81 that faces the cover 5. Afterthe lugs 95 have snapped in, a cam 97 of each lug 95 rests with itssharp edge against a sharp-edged clawing side 99 of the recess 96 in thelocking direction, so that an unintentional detachment of the supportpart 81 from the housing cover 5 is impossible even under extremepressure conditions in the interior of the filter. The other three sidesof the recess 96 may be provided in the releasing direction with thebevelled surfaces 100 depending on which type of release (turning oraxial displacement) is intended. At the top end 101 of the support part81, the recesses 96 are molded in in such a way that a ring 102, thelatter extending all around, is still present on the support part 81.

When the cover 5 and the support part 81 are mounted, the support part81 is pushed with its ring 102 over a molded incline 103 of thehook-shaped lugs 95 in the direction of the bottom of the cover in sucha way that the cams 97 of the lugs 95 subsequently lock in the recesses96.

When the cover 5 and the support part 81 are dismantled, the supportpart 81 is first pushed in the direction of the cover 5, so that thecams 97 of the lugs 95 are guided across the bevelled surfaces 100 ofthe recesses 96 and come to rest on the inside against the end 101 ofthe support part 81. Subsequently, the support part 81 is turned to suchan extent that when the support part 81 is subsequently pulled off, thelugs 95 will slide across the guide bridges 104, the latter beingdisposed between the recesses 96 and connecting the end 101 of thesupport part 81 with the ring 102 of the support part 81, withoutlocking in the recesses 96.

With the shown exemplified embodiment of such a filter for liquids, aseparate and environmentally friendly waste disposal is assured when thefilter is changed due to the utilization of single materials for theindividual filter elements.

Furthermore, the special constructional embodiment of the support partreceiving the functionally required individual parts assures that theexchangeability and/or reuse of each individual part is possible, i.e.,for example, the support part can be completely exchanged or reused,only the seals and/or the filter elements can be replaced separately, orthe valuable filter housing can be reused per se because no otherindividual parts (wear parts) are rigidly integrated in said housing.Such a design of the filter for liquids permits a use according to theunit construction system, so that it is even possible to omit, forexample the one or other valve without any further measures.

We claim:
 1. Filter for liquids, comprisinga filter housing including aninlet means and an outlet means, a cover separable from said housing,said housing containing at least one ring-shaped, exchangeable filterelement separable from said housing having two axial ends and having aninterior space, each said axial end defining an inside and a face side;a support part within said housing, said support part being separablefrom the at least one filter element and extending at least partlycentrally through the interior space of the filter element, and saidsupport part being supported on the cover by a support means; first andsecond radial inner seals separating a crude space surrounding anexterior of said filter element from a clean space contained with theinterior space of the filter element, and said radial inner sealsmounted within said filter element at the axial ends of the filterelement; said separable filter element being folded star-shaped andsealed on each said face side by an end disk and provided on the insideat each of its two axial ends with a sleeve having a radial innersurface for resting against a radial outer surface the radial innerseals; said radial inner seals comprising said first radial sealpositioned on the support part for separating the crude space from theclean space and said second radial inner seal positioned on said outletmeans; and an overflow valve contained within the support part forestablishing a flow connection between said crude space and saidinterior space when a pressure difference therebetween exceeds apredetermined value.
 2. Filter for liquids according to claim 1, furthercomprising a sieve contained within the support part.
 3. Filter forliquids according to claim 1, further comprisingan axially extendinglongitudinal axis in said support part; circumferentially distributed,axially extending support ribs extending along said longitudinal axisand molded on an exterior surface of the support part for supporting thefilter element.
 4. Filter for liquids according to claim 1, furthercomprisingwherein said outlet means comprises a tubular short pipeprojecting into the interior Space of the filter element said pipe beingcentrally shaped by molding on the filter housing for receiving saidsecond radial inner seal separating the crude space from the cleanspace.
 5. Filter for liquids according to claim 4,wherein said secondradial inner seal lips extending all around said second radial seal. 6.Filter for liquids according to claim 4, wherein said housing has feedopenings, and wherein there is a return check valve for closing the feedopenings, said return check valve including a portion that rests againstthe short pipe on the outside, whereby said return check valve preventsflow out of said crude space via said feed openings.
 7. Filter forliquids according to claim 6, wherein said portion of the return checkvalve includes the second radial inner seal.
 8. Filter for liquidsaccording to claim 4, further comprising a return check valve withinsaid short pipe for preventing flow into said interior space via saidpipe.
 9. Filter for liquids according to claim 1, furthercomprisinghousing cover for the filter housing, and wherein said supportmeans includes a releasable snap connection means on the support partfor detachably connecting the housing cover to the support part. 10.Filter for liquids according to claim 9, wherein the releasable snapconnection means comprises:at least two flexible, hook-shaped lugs onthe housing cover; and means defining closed recesses on support partwhich engage said lugs; each means defining a closed recess has in alocking direction at least one sharp-edged clawing side means; eachmeans defining a closed recess has a bevelled surface and each lug hasin a direction of release at least one molded incline; and guide bridgemeans for the lugs are circumferentially disposed between the recesses.11. Filter for liquids according to claim 10,wherein said housing coverhas an inner bottom; said hook-shaped lugs projecting on the cover innerbottom into the interior of the housing engage in said closed recessesin the support part at the end of the support part facing the cover;said lugs each having a cam having a sharp edge, whereby the cams of thelugs in each case rest with their sharp edge in the locking directionagainst the sharp-edge clawing side means of each recess.
 12. Filter forliquids according to claim 10,wherein there are four circumferentiallydistributed lugs.
 13. Filter for liquids according to claim 1, furthercomprising:wherein said outlet means comprises a tubular short pipeprojecting into the interior space of the filter element, said pipebeing centrally shaped by molding on the filter housing for receivingsaid second radial inner seal separating the crude space from the cleanspace; and wherein said support means includes means for detachablyconnecting the housing to the support part.
 14. Filter for liquidsaccording to claim 1, further comprisinga housing cover for the filterhousing wherein said support means includes means for detachablyconnecting the housing cover to the support part, a tubular short pipeprojecting into the interior space of the filter element, and a returncheck valve within said short pipe for preventing flow into saidinterior space via said pipe.
 15. Filter for liquids according to claim1, further comprisingwherein said outlet means comprises a tubular shortpipe projecting into the interior space of the filter element, said pipebeing centrally shaped by molding on the filter housing for receivingsaid second radial inner seal separating the crude space from the cleanspace; and, wherein said support means includes a releasable snapconnection means on the support part for detachably connecting thehousing cover to the support part.
 16. Filter for liquids according toclaim 15, further comprising a return check valve within said short pipefor preventing flow into said interior space via said pipe.
 17. Filterfor liquids, comprisinga filter housing including an inlet means and anoutlet means, a cover separable from said housing, said housingcontaining at least one ring-shaped, exchangeable filter elementseparable from said housing having two axial ends and having an interiorspace, each said axial end defining an inside and a face side; a supportpart within said housing, said support part being separable from the atleast one filter element and extending at least partly centrally throughthe interior space of the filter element, and said support part beingsupported on the cover by a support means; first and second radial innerseals separating a crude space surrounding an exterior of said filterelement from a clean space contained with the interior space of thefilter element, and said radial inner seals mounted within said filterelement at the axial ends of the filter element; said separable filterelement being folded star-shaped and sealed on each said face side by anend disk and provided on the inside at each of its two axial ends with asleeve having a radial inner surface for resting against a radial outersurface the radial inner seals; said radial inner seals comprising saidfirst radial seal positioned on the support part for separating thecrude space from the clean space and said second radial inner sealpositioned on said outlet means; and an overflow valve contained withinthe support part for establishing a flow connection between said crudespace and said interior Space when a pressure difference therebetweenexceeds a predetermined value; wherein said outlet means comprises atubular short pipe projecting into the interior space of the filterelement, said pipe being centrally shaped by molding on the filterhousing for receiving said second radial inner seal separating the crudespace from the clean space; and a return check valve within said shortpipe for preventing flow into said interior space via said pipe. 18.Filter for liquids, comprisinga filter housing including an inlet meansand an outlet means, a cover separable from said housing, said housingcontaining at least one ring-shaped, exchangeable filter elementseparable from said housing having two axial ends and having an interiorspace, each said axial end defining an inside and a face side; a supportpart within said housing, said support part being separable from the atleast one filter element and extending at least partly centrally throughthe interior space of the filter element, and said support part beingsupported on the cover by a support means; first and second radial innerseals separating a crude space surrounding an exterior of said filterelement from a clean space contained with the interior space of thefilter element, and said radial inner seals mounted within said filterelement at the axial ends of the filter element; said separable filterelement being folded star-shaped and sealed on each said face side by anend disk and provided on the inside at each of its two axial ends with asleeve having a radial inner surface for resting against a radial outersurface the radial inner seals; said radial inner seals comprising saidfirst radial seal positioned on the support part for separating thecrude space from the clean space and said second radial inner sealpositioned on said outlet means; and an overflow valve contained withinthe support part for establishing a flow connection between said crudespace and said interior space when a pressure difference therebetweenexceeds a predetermined value; and wherein said support means includesmeans for detachably connecting the housing cover to the support part.19. Filter for liquids, comprisinga filter housing including an inletmeans and an outlet means a cover separable from said housing, saidhousing containing at least one ring-shaped, exchangeable filter elementseparable from said housing having two axial ends and having an interiorspace, each said axial end defining an inside and a face side; a supportpare within said housing, said support part being separable from the atleast one filter element and extending at least partly centrally throughthe interior space of the filter element, and said support part beingsupported on the by a support means; first and second radial inner sealsseparating a crude space surrounding an exterior of said filter elementfrom a clean space contained with the interior Space of the filterelement, and said radial inner seals mounted within said filter elementat the axial ends of the filter element; said separable filter elementbeing folded star-shaped and sealed on each said face side by an enddisk and provided on the inside at each of its two axial ends with asleeve having a radial inner surface for resting against a radial outersurface the radial inner seals; said radial inner seals comprising saidfirst radial seal positioned on the support part for separating thecrude space from the clean space and said second radial inner sealpositioned on said outlet means; and an overflow valve contained withinthe support part for establishing a flow connection between said crudespace and said interior space when a pressure difference therebetweenexceeds a predetermine value; wherein said outlet means comprises atubular short pipe projecting into the interior space of the filterelement, said pipe being centrally shaped by molding on the filterhousing for receiving said second radial inner seal separating the crudespace from the clean space; and a return check valve within said shortpipe for preventing flow into said interior space via said pipe; and,wherein said support means includes means for detachably connecting thehousing cover to the support part.
 20. Filter for liquids, comprisingafilter housing including an inlet means and an outlet means, a coverSeparable from said housing, said housing containing at least onering-shaped, exchangeable filter element separable from said housinghaving two axial ends and having an interior space, each said axial enddefining an inside and a face side; a support part within said housing,said support part being separable from the at least one filter elementand extending at least partly centrally through the interior space ofthe filter element, and said support part being supported on the coverby a support means; first and second radial inner seals separating acrude space surrounding an exterior of said filter element from a cleanspace contained with the interior Space of the filter element, and saidradial inner seals mounted within said filter element at the axial endsof the filter element; said separable filter element being foldedstar-shaped and sealed on each said face side by an end disk andprovided on the inside at each of its two axial ends with a sleevehaving a radial inner surface for resting against a radial outer surfacethe radial inner seals; said radial inner seals comprising said firstradial seal positioned on the support part for separating the crudespace from the clean space and said second radial inner seal positionedon said outlet means; and an overflow valve contained within the supportpart for establishing a flow connection between said crude space andsaid interior space when a pressure difference therebetween exceeds apredetermined value; and, wherein said support means includes areleasable snap connection means on the support part for detachablyconnecting the housing cover to the support part.
 21. Filter forliquids, comprisinga filter housing including an inlet means and anoutlet means, a cover separable from said housing, said housingcontaining at least one ring-shaped, exchangeable filter elementseparable from said housing having two axial ends and having an interiorspace, each said axial end defining an inside and a face side; a supportpart within said housing, said support part being separable from the atleast one filter element and extending at least partly centrally throughthe interior space of the filter element, and said support part beingsupported on the cover by a support means; first and second radial innerseals separating a crude space surrounding an exterior of said filterelement from a clean space contained with interior space of the filterelement, and said radial inner seals mounted within said filter elementat the axial ends of the filter element; said separable filter elementbeing folded star-shaped and sealed on each said face side by an enddisk and provided on the inside at each of its two axial ends with asleeve having a radial inner surface for resting against a radial outersurface the radial inner seals; said radial inner seals comprising saidfirst radial seal positioned on the support part for separating thecrude space from the clean space and said second radial inner sealpositioned on said outlet means; and an overflow valve contained withinthe support part for establishing a flow connection between said crudespace and said interior space when a pressure difference therebetweenexceeds a predetermined value; wherein said outlet means comprises atubular short pipe projecting into the interior space of the filterelement, said pipe being centrally shaped by molding on the filterhousing for receiving said second radial inner seal separating the crudespace from the clean space; a return check valve within said short pipefor preventing flow into said interior space via said pipe; and, whereinsaid support means includes a releasable snap connection means on thesupport part for detachably connecting the housing cover to the supportpart.